1. Technical Field
This invention relates to a developing device, an image forming apparatus and an image forming method for conveying toner in a housing to outside the housing by causing a toner carrying roller to carry the toner and thereafter collecting the toner again into the housing.
2. Related Art
In a developing device and an image forming apparatus for conveying toner in a housing to outside the housing by causing a toner carrying roller to carry the toner and thereafter collecting the toner again into the housing, the leakage of the toner to the outside of the housing is prevented by bringing a seal member into contact with a surface of the toner carrying roller. For example, in a developing device disclosed in JP-A-H06-075469, the leakage of toner is prevented by bringing a seal member into contact with a surface of a development sleeve.
In the apparatus constructed as above, the seal member discharges the electric charges of the toner, thereby making the toner easily separable from the toner bearing roller. In return, the seal member itself is electrically charged and electric charges produce repulsive forces to the toner on the toner carrying roller, thereby scattering the toner and weakening an action of the seal member to discharge the toner. Therefore, the toner on the toner carrying roller may not be satisfactorily renewed and problems such as image fogging could occur.
Concerning this, it is disclosed in the above literature that a discharging member or the seal member having a discharging function is directly brought into contact with the development sleeve near an end of the development sleeve to set the neutralizing member or the seal member at the same potential as the development sleeve.